There actually were Undead concepts done and a storyline written. However Konstantin wouldn't recall this as Undead were cut before him joining the team. I will have to try and dig up and see if I have some of that still. A funny tidbit about the undead, they weren't cut due to lack of interest, difficulty, or funding. We cut Undead because at the time Warcraft 3 was new and we considered them a competitor, so we wanted to separate ourselves from them to make DoF look more original. We didn't anticipate it would take another 7 years to finish the game

Maakvir were the Undead replacements that we threw in to be original, balancing issues as stated in the article were the reason for the cut, because we didn't want to have to commit to putting in large water bodies in each map to accommodate them, as well as it would very easy for players to find their bases; find the lake, you find the Maakvir.